Cotack-goniometer.



No. 655,005. Patented m 3r, I900.

s. PENFIELD.

CONTACT GDNIOHETER.

{Application flled Apr. 2, 1900,) (No Model.) I 2 Sheets-Sheet I.

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SAMUEL LEWIS PENFIELD, or} NEW HAVEN, CONNECTICUT.

CONTACT-GONIOMETER.

SPECIFICATION forming part of Letters Patent N0. 655,005, dated July 31, 1900.

Application filed April 2,1900, Serial No. 11,049. (No model-1 To all whom it may concern.-

Be it known that I, SAMUEL Lnwis PEN- FIELD, of New Haven, in the county of New Haven and State of Connecticut, have invented a new Improvement in' Contact-Goniometers, (Case 13;) and I do hereby declare the following, when taken in connection with the accompanying drawings andthe letters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawingsconstitute part of this specification,

andrepresent, in

Figure 1, a plan View of the card of my improved goniometer; Fig. 2, a plan view ofthe card, showing the swiveled measuring-arms applied to its base-line; Fig. 3, a detached plan view of the arms, one of which is partly broken away; Fig, 4, a view showing one of: the modified forms which the swiveled measuring-arms may assume and illustrating themanner of applying them to the base-lineof the card; Fig. 5, a detached plan view of the said modified arms.

My invention relates to an improvement in that class of instruments used in crystallography for measuring thefihterfacial angles of crystals and called cont-act-goniometers to distinguish them from reflection-goniometers, the object being to produce a simple, convenient, and accurate instrument constructed with particular reference to cheapness of production. p

With these ends in view my invention con sists in a contact-goniometercomprising a card provided with a divided semicircle and having a baseline, and two independentlyorganized ordetached measuring-arms swivs eled together between their indicating and their measuring ends andada'pted to be applied to the base-line of the card, so that: while the edge of one arm is in Contact with that line the other arm will be brought into position upon the card to indicate, in conjunction with the degree-lines thereof, the angle measured by the measuring ends of the measuring-arms.

Myinvention further consists in certain details ofconstruction,' as will be hereinafter desCPibedJand pointed out in'the claims.

In carrying out my invention, as shown in Figs. 1, 2,- and 3, I employ a cardboardcard A, provided with a divided semicircle'B, the degree-lines of which are preferably extended inward to a small semicircle B surrounding semicircles.

the center B of the circle, the said center being indicated by the extreme inner end of aline B placed at a right angle to the baseline B4 of the card. The inward extensions of the degree-lines arestopped at the said semicircle B, because if it were practicable .to draw them to a focus at the said point B representing the true center of the circle, they would appear to the unassisted eye to run together. The semicircles B and B, I have indicated by broken lines for conven ience of illustration and because it is impossible to put on the drawings all of the degreelines which themselves establish the two There is no difiiculty, of course, inengraving those lines; but for thepurpose of a Patent Office drawing they cannot be drawn. With such a card I employ two independently-organized or detached measuring-arms O and D, swiveled together-between their measuring ends'c and cl and their indi eating ends '0 and d by an eyelet E, applied to the arms, so as to make their swiveling movement so stiff as never to take place unassisted by the user of the instrument. As shown, the arms 0 and D correspond to each other in length and width, though this is not imperative. They are swiveled together not at their longitudinal centers, but sufticiently at one side thereof to produce indicating ends long enough to reach from the base-line of the card to or beyond the outer edge of the divided semicircle B, where the numbers in dicating the degrees are located. By preference the arm 0 is made'from a strip of trans parent cellul0id,while the arm D is made from a corresponding strip of vulcanized or hard fiber. The indicating end c of the transparent measuring -arlnOis providedwith a long indicating-line c placed in its longi tudinal center in position to intersect the imaginary center of the eyelet E. The measthe measuring ends 0 and d of the" measuring arms are brought into Contact with the faces of the crystal and the plane of the arms kept as nearly as possible at a right angle to the edge formed by the intersection of the faces.

The measuring-arms are then removed from the crystal and applied to the card in such a manner that theinneredge of the opaque measuring-arm D will be in contact with the base-line of the card, upon which the said.

edge of the said arm is then shifted in one ter of the circle. now be found to vbe parallel or substantially parallel with one of the long degreedines of theidivided semicircle B. This degree-line, which will be seen through the transparent arm, will indicate by its position among its fellows the angle measured by the measuring ends of the arms. By reading in this way the measurements obtained from the;indieating-line a through the transparent indicating arm I am enabled to secure not only Very-accurate measurements, but to secure such measurements very quickly. Instead of locating the indicating-line c in the center of the indicating end 0' of the measuring-arm G the said line may be located on either side of the center of the said end of the said arm. parallel with one edge of the said end of the arm. It might even be dispensed with altogether and one edge of the said end of the arm used in its place to read from. p

In the modified construction shown by Figs. Land 5 I employ a cardboard card corresponding toth'e card A; but instead of employing one opaque and one transparent measuring-arm I employ two independentlyorganized or detached opaque measuringarms and G, swiveled together by an eye let H,-located between their measuring ends f'and-g and'their indicating ends f and g.

\ In using these arms their measuring ends f and g are brought as nearly into contact with thefacesof the crystal as may be and the plane of the arms kept as nearlyaas possible I at a right angle to theedge formed by the intersection of the said faces. The swiveled arms are then ap lied to the card, so that the point ofdivergence of the adjacent edges of the indicating ends f and g of the arms will exactl'ycoincide with the point B representing the center of the divided semicircle Bof thecard, as shown in Fig. 4. At this time the inner edge of the arm G should exactly coincid-e with the base-line of the card. The edge f of the arm F will now be parallel or sub- ',stantially parallel with one of the long degree-lines-of the divided semicircle, and that line will by its position therein indicate the in: terf-acial angle of the crystal measured by the measuring ends of the arms. If necessary, the measuring ends of the arms. may be snipped ofi to adapt them to be applied to the crystal, depending upon the size and position thereof. My purpose is toprovideeachgoniometer with It must, however, be

one or more pairs of these hard-fiber arms, so that some can be snipped, as described, and some kept in their original form.

In view of the modifications suggested and of others which may obviously be made I would have it understoodthat I do'not limit myself to the exact construction herein shown and described, but hold myself at liberty to make such changes as fairly fall within the spirit and scope of my invention.

Having fully described my invention, what I'claim as new, and desire to secure by Letters Patent, is

1. A contact-goniometer comprising a card provided with a divided semicircle having a base-line,'and two independently-organized or detached measuring-arms swiveled together between theirindicating ends and-their measuring ends, and one of them being made of a transparent materialthrough which the divisions of the'said semicircle may be read, the said arms being adapted to be temporarily applied to the base-line of the card so that while the edge of one arm is incontact with the said base-line, the other arm will be brought into position upon the card to indicate in conjunction with the degreelines thereof, the-angle measu red by the measuring ends of the arms.

2. A contact-goniometer, comprising a card provided with a divided semicircle and having a base-line, and two independently-organized or detached measuringarms swiveled together between their indicating ends and their measuring ends, and-one-of them'ha-ving a transparent indicating end through which the divisions of the said semicircle maybe read, the said arms being adapted to be temporarily applied to the base-line of the-card, so that while the edgesof one-arm are incontact with the said base-line, the other arm will be brought intoposition upon the card to indicate in conjunction with the degreelines thereof, the angles measured by the measuring ends of the arms. I

3. A contact-goniometer, comprising a card provided with a divided semicircle and having a base-line, and two independently-organized ordetached measuring-arms swiveled together-between their indicating ends and their measuring ends, and made of readilydivisible material toadapt them to be-cut ed to meet the requirements of use, and adapted to be temporarily applied to the base-line of the card, so that while theedge of one armis in contact with that base-line the other arm will be brought into position upon the card to indicate in conjunction with the degreelines thereof, the angles measured by the measuring ends of the arms. p In testimony whereof I have signed this specification in the presence of two subscrib- .ing witnesses. 

